Fuse



1. A. NELSON.

FUSE. APPLICATION FILED JAN. 12, I920.

Patented July 11, 1922.

Him/T01? Jo/UZA JVAEMSOIL,

ATTORNEYS UNITED STATES PATENT OFFICE.

rusn.

Specification of Letters Patent.

Patented July 11. 1922.

Application filed January 12, 1920. Serial No. 350,862..

To all whom it may concern:

Be it known that I, JoHN ALLAN Nansen, a citizen of the United States, and a resident of Charleston, in the county of Charleston and State of South Carolina, have invented certain new and useful Improvements in Fuses, of which the following is a specification.

My invention is an improvement in thermal cut-outs or fuses, and more particularly to fuses of the plug type.

An important object of my invention is to provide a fuse which, when ruptured by an excessive flow of current, may be easily detected without resorting to the use of testing apparatus.

Another important object is to so locate the blowing portion of the fusible element, that when the fuse has blown, the blown portion will be clearly visible through the mica covering of the fuse.

A further object is to provide a fuse which will be inexpensive to manufacture, simple of construction and durable.

Other objects will become apparent during the course of the following description.

In the drawings forming a part of this specification, and in which like numerals are employed to designate like characters throughout the same,

Figure 1 is a central vertical section through one form of my invention,

Figure 2 is a plan view of the same,

Figure 3 is a plan view of the same showing the fusible element ruptured,

Figure 4 is a central vertical section through another form of my invention, and

Figure 5 is a plan view of the same.

Figure 6 is a detailed view illustrating the means for holding the rod carrying the central contact of the fuse plug against longitudinal movement.

In Figures 1 to. 5 inclusive, a cup-shaped body portion 10 formed of insulating material, is provided exteriorly with a screw threaded sleeve 11 which has its upper extremity bent inwardly to form a flange 12 adapted. to overlieand engage a transparent cover or window 13 and hold it securely to the body portion 10. V

Referring to Figures 1, 2 and 3, wherein is shown a simple form of my invention, a fusible element 14, preferably in the form of a strip, is mounted centrally within the body portion 10 to a contact member 15 secured thereto, and rises vertically to a point near the transparent cover 13 where it is bent substantially at right angles as shown at 16. The fusible element 14 is secured to the outer sleeve 11 by any suitable means and thus a completed circuit is formed when the plug is screwed into a socket supplied with an electric current.

A portion of the fusible element 14 is partially reduced in cross sectional area as shown at 17, so that the blowing of the fuse may be confined to the upper portion of the body 10 and in close proximity to the window 13. V

In Figure 3 at 18 the fuse is shown in a ruptured condition, after the passing of an excessive current of electricity,clearly illustrating the purpose of my invention.

Referring to Figures 4 and 5, disclosing another form of my invention, a fusible element 19 is spirally arranged in the upper portion of the body 10 and has its inner end mounted upon a vertical rod 20 which is preferably constructed of iron or brass, or other metal having a higher melting point than that of the fusible element 19. In this form of my invention, the entire fusible element is arranged just beneath the transparent cover 13 so that when the fusible element 19 blows the result will be a gap in the fusible element 19 similar to that shown in Figure 3.

The vertical rod 20 is provided near its lower extremity with stamped out portions 21 and 22 adapted to be bent in opposite directions and to engage the body portion of the fuse, thus securing the rod in a rigid position. The end of the rod is secured to the contact point 23.

In the use of the invention when an overload current passes through the fusible element 14, or the element 19, causing it to heat and finally melt, the circuit is broken. It is clear that in both forms of my invention I have localized the blowing point of the fuse in the immediate vicinity of the transparent cover, so that when the fuse has blown the ruptured portion thereof will be plainly visible. through the transparent cover, regardless of any slight discoloration due to a the evolution of gases in the body portion of the fuse.

It is to be understood that various changes in the size, shape and arrangement of parts may he resorted to without departing from the spirit of the invention or the scope of the subjoined claim.

unity to the transparentclosure, projections extending from said rod and engaging the bottom surface of the body portion of the plug and adapted to cooperate with the metallic button tor holding said rod against longitudinal movement, and a coiled fuse element having its inner end connected to the upper end of the rod and its other end ex'ended through the side wall of the body portion of the plug and connected with the threaded metallic sleeve.

JOHN ALLAN NELSON. 

